The water hyacinth was first reported at the beginning of the twentieth century in the Nile delta in Egypt and in the province of Natal, South Africa. It is an invasive aquatic plant that originated in Brazil, where it developes mederately in its natural habitat. Introduced to Africa as an ornamental plant, in less than a century it spread to more than 50 countries around the world. These species can block oxygen supply for underwater life, navigation, agricultural irrigation canals and hydroelectric dams. Its thick vegetal carpet acn double in area in 12 days. No effective means of destryoing this invader has been found to date, but organic methods could serve to limit of its proliferation. Only 1% of introduced species cause major ecological and economic losses.